feat: piano roll shows all same-track MIDI items notes as active

app/static/js/services/ghostNoteExtractor.js

@@ -23,6 +23,7 @@
       if (!track.midiItems || !track.midiItems.length) continue;
       if (track.muted) continue;
 
+      var isSameTrack = track.id === targetTrackId;
       var trackGhostNotes = [];
 
       for (var j = 0; j < track.midiItems.length; j++) {
@@ -32,7 +33,10 @@
         var itemStartBeat = item.startTime / secondsPerBeat;
         var itemEndBeat = (item.startTime + item.duration) / secondsPerBeat;
 
-        if (itemStartBeat >= windowEndBeat || itemEndBeat < windowStartBeat) continue;
+        // Same-track items always contribute notes (show whole track); cross-track only when overlapping the window
+        if (itemStartBeat >= windowEndBeat || itemEndBeat < windowStartBeat) {
+          if (!isSameTrack) continue;
+        }
 
         var notes = item.notes || [];
         for (var k = 0; k < notes.length; k++) {
@@ -40,7 +44,7 @@
           var noteAbsStart = itemStartBeat + (note.start_beat || 0);
           var noteAbsEnd = noteAbsStart + (note.duration_beats || 1);
 
-          if (noteAbsStart >= windowEndBeat) continue;
+          if (noteAbsStart >= windowEndBeat && !isSameTrack) continue;
 
           trackGhostNotes.push({
             id: 'ghost_' + (note.id || Math.random().toString(36).substr(2, 9)),
@@ -59,6 +63,7 @@
           track_id: track.id,
           track_name: track.name,
           track_color: track.color || '#6b7280',
+          isSameTrack: isSameTrack,
           notes: trackGhostNotes
         });
       }